Chevy Cavalier, 2003, 40,000

I went to Midas for two brake pads. I was charged $350. Is that normal? The mechanic said that he would have to break the lugnuts on the tires because he claimed he could not unscrew them. I told him that I needed them to drive back home. He and the manager told me that they were for decoration purposes only and that it would be safe to drive without them. Since I was worried of the deteriorated brake pads, I agreed that the mechanic could break off the lugnuts in order to change my two brake pads. I'm very concerned that it is unsafe to drive without these lugnuts. Couldn't the tire simply fall off while I'm driving? Aren't these Midas workers lying? I would appreciate any feedback on this problem.